Nuclear Magnetic Resonance (NMR) spectra of 15N and 13C nuclei in proteins and peptides will be studied using recently developed indirect detection techniques (HMP) which are highly sensitive. The 15N shifts will be investigated as indicators of local hydrogen bonding, and secondary and tertiary structure. The 13C shifts and coupling pattern will be used for unequivocal connectivity assignment, side chain characterization, and conformational analyses. These studies will investigate the role that HMP-NMR can play in structural and conformational studies of proteins and peptides related to a wide range of fundamental biochemical problems, e.g. effector/receptor and protein nucleic acid interactions, enzyme mechanisms, and antibody/antigen recognition. These problems are central to advancing our knowledge of the molecular bases of disease processes. 15N-1H amide shifts will be correlated with hydrogen bonding, amide proton exchange with solvent, and secondary structure in a range of proteins and peptides, -- trypanothione, apamin, [1-pen] oxytocin, bovine pancreatic trypsin inhibitor (BPTI), neurophysin, and adenylate kinase. 13C-1H shifts will be used in these compounds to extend techniques of assignment to larger molecules than presently possible, and with 15N and 1H shifts to investigate differences between solution and crystal structures in BPTI, and to investigate solvent accessibility, and positions of turns. In addition to these spectroscopic analyses, modified NMR experiments will be tested for 13C-1H correlation over several bonds using HMP-NMR. Overall, these studies should test critically how 15N and 13C spectra can be used for conformational studies of proteins.